The objective of this research is to develop efficient new procedures for synthesizing several alkaloid groups including pyrrolizidines, indolizidines, quinolizidines, and yohimbanes. The well-known cationic polyene cyclization reaction is to be tested as a general method of preparing members of these, and possibly other, medicinally valuable alkaloid families. More specifically, new initiators of the reaction are to be tested which will allow relatively acid-sensitive nitrogen functional groups to be present in the cyclization precursor. the resulting multicyclic, nitrogen-containing products will then be converted to known natural products such as retronecine (the precursor of indicine, N-oxide, a potent anti-tumor alkaloid derivative) or reserpine (the most important hypotensive agent used in this country today). The development of this methodology would open the door for the synthetic organic chemist to synthesize any number of alkaloids of the aforementioned types, the range of biological activities of which includes anti-tumor, anti-hypertensive, local anesthetic, neuromuscular blocking, anti-spasmotic, anti-inflammatory, hepetotoxic, and carcinogenic activity.